如何让 php 严格解析 php.ini？

Question

The php command doesn't seem to check whether values in php.ini make sense. Here is an example:

$ echo 'memory_limit = foobar' > /tmp/php.ini
$ php -c /tmp -r 'printf("%s\n", ini_get("memory_limit"));'
foobar

How can I ask php to fail loudly when php.ini contains junk like this?

Answer 1

You probably can't.

• Ini-options are predefined with types (sort of).
• Thus they're not checked by the ini parser.
• Only the modules registering ini options ever actually interpret or complain about them. (They rarely do.)

In the case of memory_limit, it's predefined as

PHP_INI_ENTRY("memory_limit", "128M", PHP_INI_ALL, OnChangeMemoryLimit)

• Which means it's just a string.
• And it's interpretation is left up to the standard string to long parser zend_atol
• Somewhat of a core and reused function, thus does not interact with the error log
• And it just cares about numbers and some optional quantifier suffix G or M eg
• Anything else (garbage string) is interpreted as zero.

And for the purposes of memory_limit any 0 value is discarded. Because, you know, that wouldn't make sense for maximum memory usage.

Also PHP here simply assumes that at least one of all the possible php.ini s contains some sort of valid or sane default. So that's why ( I would say) there's no loud warning for this. It's just not commonly needed. Which again - my opinion - is somewhat of a valid design choice: don't overoptimize for edge cases.